So if this is only drawing 550ma then the diodes should not be getting hot not warm but hot. Another mystery.

The picture shown is a strong indication of a IF problem.

the alignment is most likely off, and is messing the video up.

Sams shows c1 and c2a in series which makes sense but this pic of the Motorola original schematic note the c1 and c2a is it me or is this showing 2 negatives together +— — + I have these caps in series like the sams shows.

clearly an error on the Motorola schematic.

Yes I do see that now sams is usually known for that

What I find odd is the voltages on v1 v2 210 on pin7 and pin 8 100 but I’m getting 198 pin 7 and 60 on pin 8 but if I pull v1 the voltages on pin 7 come up to 130

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

You have nothing to center on the screen, no video.
if there was something to see, then you would see the effect of the adjustment.

if you were to feed video in like before, then you would see it working most likely.

I thought the whole screen goes up and down not the image alone.

Pin 1 of 6cg7 is supposed to have 80v on it but it has a ridiculous 180v there this tv is full of surprises.

Unless you have vertical underscan you won't see it move without video, and even if you do it's possible the osc will have enough jitter free running that you won't notice.

That said sets with electrical centering control typically run a DC current through the yoke to control centering. The pot it's self could be bad or the circuitry feeding it. Before declaring it bad though, I would definitely confirm operation with video fed in.

The vertical centering pot (R-16) is 10 ohm! It is shown on an output winding of the vertical output transformer (T-2).

jr

Yes your right I knew that lol my mistake

I wish I knew if someone fooled with the overall alignment of this set but if it has been messed with it can’t be to far out since I can make out some things on screen but of course it’s distorted.

Has anyone ever had a video detect germanium diode test good but be bad in circuit.

What you would see if your IF section was VERY messed up...
Absolute and total randomized garbage on the screen as you try to tune in something, wildly changing color (unless color killer is turned down), herringbone patterns that will react to fine tuning, but no real video info getting through at all.

You could try to replace the video det, but it most likely won't help as the problem is most likely before it.

So it seems you have 2 choices.

1)
Find someone nearby with the equipment and knowledge to help you debug and align the tuner/ IF sections.

2)
Rig it for direct A/V input, and bypass the front end for now using a easy to build video amp to match the level needed for the set.

Well I put a new video detect diode in certainly was not an easy thing to do so I’m going to try it and as for alignment there is only one coil that shows the slug was moved it’s the same coil where the diode is A4 so if that was messed with then if I’m careful I could turn the slug in or out counting the turns in or out and see what occurs I have nothing to lose at this point.

No difference but the video injecting still works and I did notice the ac waving in the screen for the first few minutes caps are good unless ac is getting in somewhere. The block lines are not in the picture the camera is causing the lines.

How can I stop the blue arc that is between the rectifier and the 2 wires for the 3 volt heater

Well at this point it doesn’t matter how much current this set is drawing because the 3 voltages are low again and I still think there is some stray voltage getting in somewhere affecting the video and the voltages. being the output diode gets really hot which I’m sure is not supposed to get this hot.

inducted corona, mostly harmless, my hoffman colorcaster did the same thing, just keep the wires as far away from the tube as you can, I did this by cutting the bottom off an old pill bottle and putting it around the tube as a guide/form to keep the wires away from the tube.

Thought it may break the glass on the tube. Smell of corona is not bad it cleans the air.

Again, don't take the voltages listed in the SAMs as gospel, expect them to differ by some degree.
Your screen showing good video with direct input is a indication that power is stable.

As for the hot diodes, this is not suprising, they are under heavy load, but if there is doubt, replace.

As suggested before, these are cheap and much better than the OEM ones.

https://www.mouser.com/ProductDetail...2B4kkscA%3D%3D

With video injected the horizontal and vertical are good stable picture but I can’t imagine where the stray voltage could be coming from because obviously it’s still pulling the voltage down but it seems not all the time or even where to start to look. There is a 390 ohm resistor to ground I clipped it and it measures 390k the voltages are low in v1 v2 but if I leave the resistor off the voltages jump up.

My set has a 3A3-C, and the heater wires were getting a bit close and causing a blue glow, all I did was use a plastic spacer around the tube that was about 10-15% larger than it's diameter to keep the wires away, it's working perfectly.

Problem I have is I only have a 360ohm resistor not a 390ohm. I could try it see what happens.

R47? I guess you missed that when you checked resistors in the area before, but I did mention that the ones off the cathodes are the ones most likely to be bad for some reason.

Yes r47 is it me orange. Blue. Brown is 360 ohm correct? I don’t have a 390 but this meter just yesterday measured 360 ohm and the 390 in the set measured 390k .

360 is close enough to try, but do take a look at the markings on what is coming out, just to be sure there is not a production change.

390ohm is what’s in there 360ohm made no difference v1 v2 pin8 should be 100v but 60v on v1 and 55v on v2

the 6EH7s are new? & what was the voltage on pin 7 V 1 & 2 ?

I was thinking Matthew antenna input is not making it to the first IF because of a bad trap it supposed to measure 15k but it’s a 2 connection and to measure it I would think it would have to be turned and if I do that I couldn’t get it back.

I was thinking of a “worst case scenario”, but not being able to see and test it, there is no way to know.

This may be a case of the dreaded “silver mica disease” bad caps in the coils L4 L5, causing wrong voltages on pins 7 & 8, if true, then hopes of getting it working is very low.

6eh7 all new 2 sets v1 pin 2 7v v2 12v v3 pin 2 0

the important voltage is pins 7 & 8 on the 6eh7 tubes.

Well those v1 v2 7-and 8 voltages are wrong and L4 and L5 shows they each have a .001 inside why couldn’t they be changed.

I looked inside there is ceramic caps in L4 L5 I would have to clip the ground to see if they are bad or shorted

as others have said, unlike changing resistors, changing capacitors in the IF section = 100% chance of needing to align the entire thing end to end, you would be better of replacing the 3w/2w power resistors, even if they seem OK, that are feeding power to the coils before even thinking of touching any caps in the area.

Well all I have to do is clip the ground on each cap it’s on the outside and I can then see if they are bad if they are then I’ll have to decide what to do after that. Those caps oscillate the coils correct ?

it be best not to disturb them yet, I would try fresh power resistors first.

if they are messed with, it will shift the alignment.